Net Assets in Liquidation - Additional Information (Detail)		3 Months Ended
	Mar. 31, 2011 USD ($) Unit	Sep. 30, 2015 USD ($) Trust	Mar. 31, 2015 USD ($)
Net Assets in Liquidation [Line Items]
Distributable Assets		$ 589,600,000
Cash and cash equivalents and marketable securities		803,444,000
Liquidating distributions payable in Distributable Cash for Excess GUC Trust Distributable Assets		129,700,000
Distributable Cash set aside for projected Trust fees, costs and expenses		62,500,000
Distributable Cash set aside for projected Dividend Taxes and Investment Income Taxes		2,300,000
Distributable Cash set aside for potential Taxes on Distribution		108,700,000
Distributable cash pending distribution or set aside and not available for distribution		$ 303,100,000
Number of Trust Units issued per thousand dollars of allowed general unsecured claims | Unit	1
Amount required to issue one Trust Unit per contingent rights	$ 1,000
GUC Trust Units outstanding | Trust		31,853,702
GUC Trust Units issued during the period | Trust		0
Liquidation Basis of Accounting [Member]
Net Assets in Liquidation [Line Items]
Liquidating distributions payable		$ 131,885,000	$ 7,714,000
Accrued Dividends on Holdings of New GM Common Stock			26,524,000
Dividend Expected To Be Declared [Member] | Liquidation Basis of Accounting [Member]
Net Assets in Liquidation [Line Items]
Accrued Dividends on Holdings of New GM Common Stock			$ 22,400,000